Answer:
3* (36 - 5x)
Explanation:
The total area of the flower garden is equal to the surface of the rectangle that encloses the flowers border and the sitting area minus the area of the sitting area.
Rectangle area
Three flower segments height ---- 9 feet
4 flower segments length ----------- 12 feet
Rectangle area = 12*9 ft^2 = 108 ft^2
Sitting area
Sitting area = 3x*5 = 15x
Area of the flower border (A_flwb)
A_flwb = 108 ft^2 - 15x = 3* (36 - 5x)